The present invention concerns a portable object, such as, in particular, a timepiece, including means for activating an electronic function such as an horological function. The present invention also concerns a method for controlling an electronic function of the aforementioned type.
Numerous devices for inputting data into electronic means intended for processing such data are already known. These devices may include, for example a keyboard formed of a plurality of keys, each of the keys being associated with a subjacent sensitive pad of a sensor which controls the inputting of a data item associated with the key in response to a finger being placed on the key. A keyboard of this type is for example disclosed in European Patent Application No. EP-A-0 674 247 in the name of the Applicant in which it is associated with a watch to control various functions such as time-setting or starting and stopping a chronograph. When it is fitted to a watch, such a keyboard advantageously allows the usual push-buttons to be replaced.
The keys of keyboards incorporated in watches are formed by touch-sensitive sensors of different types, for example piezo-sensitive, photosensitive, resistive or capacitive type sensors. In the latter case, the sensitive pad of each sensor can be formed by a transparent electrode formed on the inner face of the crystal. By placing a finger on a pad of the outer surface of the crystal which faces the electrode, an electric capacitor is formed between the finger and the electrode which are separated by the dielectric formed by the watch crystal. An electronic circuit sensitive to the capacitance value of the capacitor identifies the electrode set in action by placing the finger and deduces the character or operation thereby selected for one or other of the aforementioned applications.
As already stated, one of the essential advantages of keyboards with touch-sensitive keys lies in the fact that, when fitted to portable objects of small dimensions such as, in particular, a wristwatch, such keyboards enable the push-buttons which are normally fitted to such wristwatches, to be omitted. As will be easily understood, this allows the manufacturing costs of such watches to be substantially reduced, and excellent sealing thereof to be guaranteed.
A watch including control means formed by a set of touch-sensitive keys has, however, several drawbacks. One of such drawbacks lies in the fact that the touch-sensitive keys are very sensitive to the touch. Thus the user of the watch has only to inadvertently brush against one of the keyboard keys for the character or operation corresponding to such key to be selected and activated by the electronic data processing circuit.
Moreover, the touch-sensitive sensors must be constantly powered by an electric current to be able to be used when required, which poses obvious problems of electric power consumption, which are all the more important when the touch-sensitive keys in question are very particularly intended to be fitted to objects which are of small dimensions and which thus have limited power reserves.
One of the functions of a timepiece which is most frequently controlled by means of a touch-sensitive keyboard is the stop or start function of a chronograph. It has unfortunately been realised during use that such a technique is particularly awkward and difficult to implement. Indeed, a user who wishes, for example, to time a sporting event, has to take his eyes off the event to be able to find and activate the pad of the crystal corresponding to the appropriate control key for starting the chronometer. This results in timing which is often inaccurate and thus unsatisfactory for the user.
Finally, with a matrix of high density touch-sensitive keys there is a significant risk of touching the wrong sensor and thus activating the wrong key. It is clear that the surface area of a fingerprint is not small with respect to the that of a watch crystal, which it itself limited when the watch is a wristwatch. It is thus difficult to place the finger on the watch crystal above the desired electrode, without influencing the adjacent electrodes at the same time. Thus in order to identify which of the electrodes influenced was the one targeted, the electronic means incorporated in the watch have to develop complex identification strategies.
The object of the present invention is thus to overcome the above problems and drawbacks in addition to others by proposing a portable object including means allowing in particular the desired electronic function to be selected without any risk of making a mistake or inadvertently activating an undesired electronic function.
The present invention thus concerns a portable object such as, in particular, a timepiece including means for controlling at least an electronic function such as an horological function, these control means including at least a touch-sensitive key for selecting the desired electronic function, an electronic data processing circuit identifying the touch-sensitive key activated and deducing therefrom a character or operation thereby selected, characterised in that the control means further include a strain gauge allowing the selection of the desired electronic function to be confirmed and/or the electronic function to be activated, the confirmation and/or activation of said electronic function being effected by applying pressure on the portable object via the effect of which the strain gauge generates a control signal which will be applied to the electronic data processing circuit, said portable object also being able to include means able to emit an acoustic signal to indicate to a user that the desired function has actually been switched on.
As a result of these features, it is no longer necessary to power the keyboard keys permanently. When the user places a finger on one of the touch-sensitive keys of the keyboard corresponding to the character or operation which he wishes to effect, he simultaneously presses down on the portable object with his finger. Detecting the application of pressure on the portable object, the strain gauge generates, in a conventional manner, an electric signal which will be applied to an electronic data processing circuit corresponding to the different functions of the portable object. This control circuit will then switch on the touch-sensitive keyboard keys, identify which of the touch-sensitive keys was activated by the user placing his finger on it, and deduce the character or operation selected for one of other of he applications which it can control.
Consequently, the risk of seeing the user inadvertently activate a function by accidentally brushing against a keyboard key is avoided. Indeed, the character or operation corresponding to the keyboard key on which the user has placed his finger will not be selected until said user has also exerted pressure on the portable object to confirm his selection.
This latter arrangement proves particularly advantageous especially in the particular case in which the user wishes to use the timing function. Having previously placed his finger on the particular touch-sensitive key which will enable him to start the chronometer, the user will be able to watch the event, for example a sporting event, which he wishes to time closely, then to exert pressure on the portable object to start timing at the right moment, without taking his eyes off the event.
The present invention also concerns a method for controlling at least an electronic function such as an horological function of a portable object of the aforementioned type, including the step consisting in selecting the desired electronic function by applying a finger to the touch-sensitive key associated with said function, characterised in that it further includes the step consisting in exerting mechanical pressure on the portable object in order to confirm the selection of said desired electronic function and/or to activate said function and, if necessary, to generate an acoustic signal to indicate to a user that the desired function has actually been switched on.
Other features and advantages of the present invention will appear more clearly upon reading the following detailed description of an example embodiment of the portable object according to the invention, this example being given purely by way of non-limiting illustration, in conjunction with the annexed drawings, in which: